Method of and apparatus for fermenting solutions



Jan. 23, 1940. H. SCHOLLER ET AL METHOD OF AND APPARATUS FOR FERMENTING SOLUTIONS Filed April 27, 1957 2 Sheets- Sheet 1 O 0 0 0 0 O 00 O 0 o 0 a 0 0 0 Jan. 23, 1940. I H. SCHOLLER ET AL METHOD OF AND APPARATUS FOR FERMENTING SOLUTIONS Filed April 27, 1957 2 Sheets-Shea}; 2

.7nvenlor;

Patented Jan. 23, 1 940 2,188,192

UNITED STATES PATENT OFFICE ,METHOD OF AND APPARATUS FOR FERlWENTING SOLUTIONS Heinrich Scholler and Max Seidel, Solln, near Munich, Germany Application April ,27, 1937, Serial No. 139,152 In Germany May 4, 1936 11 Claims. (Cl. 195-78) This invention relates to a process of and ap- The consumption of the nutrients contained in paratus forthe continuous fermentation of soluthe supplied nutrient solution may be accelerated tions, both for obtaining products of, fermentaby the employment'of great quantities of microtion and for the cultivation of multiplying microorganisms. However, these large quantities of i 5 organisms. micro-organisms must'be kept in suspension by '5 The present invention contemplates causing a special means, for example by stirring apparatus, fermentation liquid containing micro-organisms aeration or a high flowing speed of the nutrient suspended therein by artificial means, as, for exsolution, so as to give the nutrients access to all ample, by stirring with mechanical means or the cells and so as to makeit possible to remove with air or with other gases or by the high velocquickly products o met bo s a d o c s o 10 ity of the fermentation liquid, to continuously fermentationi and alternately ascend and descend, maintaining In th pre en new o nu s fermentation the micro-organisms in suspension in the ferprocess, the special expedients employed for mentation liquid until the latter is fermented maintaining the Suspension o the micro-Organextensively or to the desired degree, so that isms are eliminated or not used after the extenl5 artificial means for maintaining the mi roe sive consumption of the nutrient substances and organisms in suspension areno long r employed before the solution-leaves the fermentation vesin the final part or the ath followed by th sel. This has the result that the smaller content sumed fermentation liquid, and feeding at least of micro-Organisms in he Con umed Solution that a portion of the micro-organisms which have is running O is d aw whieh smaller 20 settled or have been elimi ated, du to m so content'is due to the consumption of the nutripression of the means of suspension, from the ents, is still further reduced as compared with consumed fermentation liquid together with a the content of micro-Organisms n the u co part of the consumed fermentation liquid, to the sumed $0111ti0n- Especially in the a on Of place where the fresh fermentation liquid enters, micro-organisms, Such as y lactic acid e- 25 and continuously removing the remaining part term and Others, the q y f c r of the consumed fermentation liquid with a r isms drawn off with the consumed nutrient soluduced content of i rorga i tion may be so slight, according to the nutrient The process accordi t th inv ti i concentration and the construction of the fertinuous in the sense that fresh fermentation mentation apparatus, as to espo d approxi- 30 liquid or nutrient solution is continuously supm s t0 the increase In c c ses the stock plied and f r t d ii id or consumed t t of micro-organisms in the fermentation vessel solution is correspondingl r v k requires no or only slight replenishment by the In order to clearly explain th i ti t t seed of fresh micro-organisms. In contradistinc embodiment relating to the cultivation of inicrot to this, a p y of fresh m c o-organism 5 organisms such as yeast is hereafter described. seed to replace the i r s that a e However, it is to be understood that the invenh r wn may be u i p o s s for the p otion is not restricted theretosince, with the api n f f rm n i n pr du ts in which it is propriate modifications, the invention also ap-. attempted s a rule to s pp e e t s vely the plies to the production of products of fermenta- P p o o the e or e V 40 tion, such as alcohol, lactic acid, acetone, acetic The nutrient solution, in which the microacid, glycerine, butyl alcohol and other products organisms Contained therein a e aintained in obtained by means of i r rga ism suspension, is guided by stirring with mechanical In accordance with one embodiment of this mean or w a r w h other as r y high invention, in order to realize an extensive utilizavelocity o other known means until t e utrient 45 tion of the supplied nutrients, the nutrient solusolution is consumed, and in such a way as to tion is guided, until it is consumed, in such a prevent fresh or less consumed nutrient solution manner that at no point in the path of travel from mixing with this running nutrient solution thereof can fresh or less completely consumed at any point in its path of travel. The means t nutrient solution mix with it. However, if-deemployed to suspend the micro-organisms may be sired, an admixture of more completely consumed employed simultaneously for the positive progresnutrient solution may be effected at any point in sion of the nutrient solution in its path of travel.

the path of travel of the nutrient solution until In special cases where because of the kind or the the nutrients contained therein are consumed, amount of the micro-organisms used special without any harmful effect. An admixture of means are not required to maintain the microsolution having a higher, nutrient content than organisms in suspension, it is sufliclent'that the the solution circulating at the point of admixprogression of the nutrient solution in the path ture would unnecessarily lengthen the path redestined for it is effected by any kind of mequired for an extensive consumption of all the chanical means, such as pumps, injectors, etc.,

nutrients. or also by blowing in air or gases where this is on not disadvantageous for the micro-organisms used or the nutrients or products.

The nutrients that are present are extensively consumed in the path of travel of the nutrient solution. Before discharging the consumed nutrient solution from the fermentation vessel in the final portion of the path of travel of the pension are conveyed with the other portion of the consumed nutrient solution to the point where the fresh nutrient solution enters, without leaving the fermentation vessel, and mixing with the fresh nutrient solution they are again placed in suspension. Consumingthe nutrient substances, the returned micro-organisms repeat the path they have passed before.

In order to more fully explain the invention, reference is directed to the drawings accompanying this specification and wherein:

Figure 1 diagrammatically illustrates in section an apparatus havinga multiplecirculatory system which is suitable for carrying out the new process;

-Figure 2 shows a simflar apparatus with certain variations, also diagrammatically in section; and

Figures 3, 4, 5 and 6 are illustrations representing diagrammatically, and without relation to the scale, examples of the various flowing conditions in the apparatus shown in Figure 1.

For the purpose of maintaining the suspension of the micro-organisms in thenutrlent and at the same time conveying the nutrient'solution along the determined path, the apparatus shown in Figure 1 is provided with well-known arrangements 2, 3 and 4 for aerating or agitating the solution with gases (circulating'carbonic acid, indifferent gases and others) The fresh nutrient solution is supplied continuously through the inlet I and forced upward in the ascending chamber A by the air or gas bubbles ascending from the aerating arrangement 2. After a portion of the nutrients has been consumed in the ascension chamber A, the liquid descends in the descension chamber B. The nutrient solution in the ascension chamber C is again forced upward by the bubbles ascending from the aerating arrangement 3. In chambers B and C additional nutrient substances are'consumed. The nutrientsubstances still present are extensively consumed when the nutrient solution descends in the descension chamber D and is forced up again in the ascension chamber E by the bubbles ascending from the aerating arrangement 4.

From the descension chamber F the consumed nutrient solution with the micro-organisms suspended therein reaches the separation chamber G, which is not provided with any arrangement for maintaining the micr -organisms in suspension. Here a portion of the micro-organisms settles or is deposited and sinks to the bottom. The micro-organisms desposited from the suspension are returned to the ascension chamber A through the canal 5, if required with the aid of mechanical means, together with a portion of the consumed nutrient solution, and here mix with the fresh nutrient solution entering at I I It is to be noted that the walls and 2| are curved rearwardly and made to extend below the 6 and I and the amounts of the liquid passing over will depend on the intensity of the rising movement in the individual ascension chambers.

A, C and E. The direction of flow obtaining in canal 5 from the settling chamber G, under the ascending chambers E and C, along to the ascending chamber A, leads the amount of liquid passing from one chamber to another chamber always positively into those chambers where the nutrients have been less extensively consumed.

The openings 6 and 1 also prevent the formation of dead spaces at the lower return points of the flow between the chambers B and C and between the chambers D and E, in which dead spaces there would be no'circulation of the liquid and which, therefore, might readily become foci of infection or at least depositing places for micro-organisms, salts and sinking substances of every kind. The compensating streams arising in the openings 6 and 1 in the case of irregular ascension in the different ascension chambers A, C and E always wash away again all the sinking substances that have a tendency to collect at the lower ends of the chambers.

The openings 6 and 1 also make it possible to clean the chambers B, C, D and E readily.

The speed of circulation of the nutrient solution through the different systems of double chambers (multiple circulatory system) A B, C D and E F may be regulated not only by the intensity of the aeration or the ascending motion produced by the stirring apparatus or other'means, but also by the size of the passage openings 8, 9 and ID at the upper return points of the flow. These openings 8, 9 and I0 may be either fixed or adjustable in cross-section.

' The openings 8, 9 and I0 are expediently of such cross-sections that the speed at which the nutrient solution flows through the chamber system is limited to a certain amount so that, after passing through a system of chambers, a good consumption of the nutrients that are present occurs even when operations are carried on with strong aeration or vigorous agitation for the purpose of producing a satisfactory suspension of the micro-organisms.

The openings II and 12 may be closed, or one of the openings may be utilized to remove periodically or continuously a portion of the sediments consisting of micro-organisms and, according to the kind and treatment of the wort, of sinking substances.

At l3, or at any other point of the fermentation vessel, fresh micro-organisms may be introduced as seed periodically or continuously for the purpose of replenishing or refreshing the stock of micro-organisms.

In the last chamber G (herein called the settling chamber) which is not provided with arrangements for maintaining the micro-organisms in suspension,

removed at M in an amount approximately equal to the quantity of nutrient solution supplied at, I. The micro-organisms still present in the consumed nutrient solution leaving at H may be obtained by removal by means of centrifuging or tration, e. g. by the addition of alkali or by the addition of phosphates, so that the consumed nutrient solution leaving at 14 contains only few micro-organisms.

The fermentation apparatus may be operated also under conditions promoting the settling of the micro-organisms per se, for example, with a suitable concentration of hydrogen ions, the use,

of micro-organisms especially tending to form flocks or other conditions that are known to promote settling. i

The micro-organisms obtained from the consumed nutrient solution which is flowing off may be returned again to the fermentation vessel, if required. This is done especially in caseswhere only products of fermentation are to be obtained, but no micro-organisms.

In cultivating micro-organisms, themicromrganisms to be obtained arated either from the iermentednutrient solution or from the sediment that is removed.

The aerating arrangements 2, 3, 4 may be replaced. by mechanical stirring apparatus, or the ascending movement of the'nutrient solution in the chambers A, C and Emay be effected by means of pumps or injectors; in which case the maintenance of the suspension of the micro-organisms may be promoted by means of a high velocity of flow. In such an embodiment it is sufficient if the high at the lower end of the ascending chambers A, C and E by means of suitable reduction of crosssection. The acceleration of the ascending movement of the nutrient solution may be produced by the same means as inv other cases, e. g. aeration, h A

the micro-organisms without'dilution of the ferstirring apparatus, pumps, injectors, etc.

Referring now to Figure 2 wherein another embodiment' of the invention is illustrated, this embodiment is provided with only two double cham-n in combination Injectors. l5 and I6 actuated with gases or liquids-for ex-'- ample, spent nutrient solutions, are employed to effect the ascension and conveyance of the nutrient solutions. It is to be noted that the ascension chambers A I5 and [6 have reduced cross-sections. It is further to be noted that the wall extends rear wardly and ma direction'parallel to the inclined bottom ofthe vessel. The lower end of the wall terminates approximately in the center of the descension chamberB".

The wall 24c'oopcrating with thebottom of the direction of flow in the canal 5' isthe same or that obtaining in1the speed of circulation may be made the same as canal 5 of Figure 1. The

the part of the consumed nutrient solution not returned with the separated microorganisms in the canal 5 rises and is continuously ,er number of such may, therefore, be sepvelocity of flow is produced and C adjacent the injectors v the vessel forms a canal 5' which is inclined as shown, so as to of the nutrient solution through this system may be regulated not only by the injectors but also by the size of the passage openings 8' and 9', which aresimilarin design and construction as passage openings 8 and 9 of Figure 1. The elements designated by the reference numerals I, ll, [2, 13f and I4 aresimilar to and function in the samemanner as the elements I, ll of Figure 1. h

Though in the embodiments described, two and three double chamber systems are illustrated, it is to be understood that the invention is not restricted thereto.

In place of the three double chamber systems A+B, C+D and E+F shown in Figure 1, a great: double chamber systems may fermentations or cultivabe made use of with -tion processes proceeding difficultly or slowly.

Wherethe fermentation or the conversion of the nutrient substances proceeds'"rapidly, it is sufficient to use only one or two double chamber systemsinstead of three.

By utilizing passage openings 8, 9 and ill of appropriate dimensions and cross-section and selected intensities of aeration, etc., various conditions of flow through the apparatus may be obtained. Figures 3, 4 5 and 6 illustrate, or the apparatus represented in Figure 1, various possi bilities of guiding and sub-dividing the flow of the liquid ,within the apparatus. The chambers and canals are referred to by the same letters and numerals used in Figure 1. It is to be noted that in each instance, nutrient solution is returned through the canal 5*to the first ascension chamber A. If desired,

through the system or be conducted to the chamber A or supply inlet I.

By using micro-organisms of, any desired concentration, processes that go on very slowly may be carried out with the new process in .a comparatively, short time. h h

The immediately produced dilution of the supplied fresh liquid of fermentation or nutrient soa part of the spent nutrient 1 solution may be made to admix with less spent nutrient solution and be caused to circulate merited wort-ora reductionof the concentration 7 the very beginning of 1. the process.

The-new process is also suitable for,;carrying sult. Th rotective action of the} product of fermentation, ,e,

a 55. against foreign m cro-organisms 1s effect ve from outprocesses of fermentation and processes of of, micro-organisms, in absolutely sterilized and propagation pure culture if the wort supplied is enter. any ventilating gases or waste gases of, fermenor-liquids, may prevent germs from entering the fermentationvessel. 5 1

' In the claimsthe expression-to suspend on equivalent thereof, is intended: totcover produc-i ready been formed,

:any gases of ventilation that are used are steri- ,v lized. The fermentation vessel may be easily sealed tightly on all sides so, that no germs can As to the discharged spent liquid and,

ing the suspension or; if the suspensionhas a1; r

to maintain the suspension.

' Since it is obvious that various changes and thereof, this invention is not restricted thereto except as set forth in the appended claims.

We claim: 1. An apparatus for the continuous fermentation of liquids comprising a vessel provided with a plurality of chambers constituting ascension chambers through which fermentation liquid travels in an ascending path and a plurality of 'chambersalternately disposed between said ascension chambers constituting descension chambers through which fermentation liquid travels in a descending path, means connecting said ascension and descension chambers to provide a multiple circulatory system so that the liquid will travel alternately in an ascending and descending path to permit uninterrupted progressive consumption of the nutrient substance, said vessel being also provided with a settling chamber through which the liquid travels in an ascending path, means to supply fermentation liquid containing micro-organisms to the first ascension chamber, means cooperating with each of said ascension chambers to suspend the micro-organisms in said fermentation liquid,'means in the lower portion of the vessel connecting the last descension chamber and settling chamber'with the first ascension chamber whereby a part of the micro-organismsis automatically returned to the first ascension chamber, and meansto withdraw consumed nutrient solution from said settling chamber.

2. An apparatus for the continuous fermentation of liquids comprising a vessel provided with a plurality of chambers constituting ascension chambers through which fermentation liquid" travels in an ascending path' and a plurality of chambers alternately disposed between said ascension chambers constituting descension chambers through which fermentation liquid travels in a descending path, means connecting said ascension and descension chambers to provide a multiple circulatory system so that the liquid will travelalternately in an ascending and descend ing path to permit uninterrupted progressive consumption of the nutrient substance, said vessel also being provided with a settling chamber through which the liquid travels in an ascend-v "ing path; means to'supply fermenation liquid I do containing micro-organisms to the first ascension chamber, means cooperating with each ,of said ascension chambers to suspend the microorganisms in said fermentation liquid and simultaneously aid in conveying the liquid through said ascension and descension chambers, means in the lower portion of the vessel connecting the last descension chamber and settling chamber with the firstascension chamber whereby a part of the micro-organismsis automatically returned to the first ascension chamber, and means to withdraw consumer nutrient solution from said settling chamber.

3. An apparatus for the continuous fermentation of liquids comprising a'vessel provided with a plurality of chambers constituting ascension chambers" througli'which fermentation liquid travels in "an ascending path and a plurality of chambers alternately disposed between said ascension chambers constituting descension chambers through which fermentation liquid travels in a descending path, means connecting said ascensionand descension chambers at-the top and bottom thereof to provide a multiple circulatory system so that the liquid will travel alternately in an ascending and descending path to permit uninterrupted progressive consumption of the nutrient substance, the means connecting the ascension and descension chambers at the top thereof being of appropriate cross-section to reg-,

ulate the flow of the liquid, said vessel being provided with a settling chamber through which the liquid travels in an ascending path, means to supply fermentation liquid containing microorganisms to the first ascension chamber, means cooperating with each of said ascension chambers to suspend the micro-organisms in said fermentation liquid, means in the lower portion of the vessel connecting the last descension chamber and settling chamber with the firstascension chamber whereby a part of the micro-organisms is automatically returned to the first ascension chamber, andmeans to withdraw consumed nutrient solution from said Settling chamber.

- 4. An apparatus for the continuous fermentation of liquids comprising a vessel provided with a plurality of chambers constituting ascension chambers through which fermentation liquid travels in an ascending path and a plurality of chambers alternately 25, disposed between said ascension chambers constituting descension chambers through which fermentation liquid travels in a descending path, means connecting said ascension and descension chambersat the top and bottom thereof to provide a multiple circulatory system'so that the liquid will travel a1- ternately in an ascending and descending path to permit uninterrupted progressive consumption of the nutrient substance, the means connecting the ascension and descension chambers at the top thereof being adjustable to regulate the flow chamber with the first ascension chamber whereby apart of the micro-organisms is automatically returned to the first ascension chamber, and means to withdraw consumed nutrient solution from saidsettling chamber.

5. An apparatus for the continuous fermentation of liquids comprising a vessel provided with 'a plurality of chambers constituting ascension chambers through which fermentation liquid travels in an ascending path and a plurality of chambers alternately disposed between said ascension chambers constituting descension chambers through which fermentation liquid travels in a descending path, means connecting said ascension and-descension chambers to provide a multiple circulatory system'so that the liquid will travel alternately inan ascending and descending path to permit uninterrupted progressive consumption of the nutrient substance, said ascension. and descension chambers being spaced from the bottom of said vessel, said vessel being also provided with a settling chamber through which .i the liquid travels in an ascending path, means to supply fermentation liquid containing microorganisms to the first ascension chamber, means cooperating with each. of said ascension chambers to suspend the micro-organisms in said fermentation liquid, and means in the lower portion of the vessel connecting the last descension chamber and settling chamber with the first ascension chamber, said means also connecting with said ascension and descension chambers.

6. An apparatus for the continuous fermentaton of solution comprising a vessel provided with a plurality of chambers constituting ascension chambers through which fermentation liquid travels in an ascending path and a plurality of chambers alternately disposed between said ascension chambers constituting descension chambers through which fermentation liquid travels in a descending path, said vessel also being provided adjacent the last descending chamber with a settling chamber through which the liquid travels in an ascending path, a canal located at the bottom of the vessel and leading from the settling chamber to the first ascension chamber, each ascension chamber having an opening at the top thereof to connect the respective ascension chamber to the descension chamber next in advance thereof, each ascension chamber hav-' ing an opening adjacent the bottom thereof to connect the respective ascension chamber to the next preceding descension chamber, the openings adjacent the bottom of said ascension chambers being connected to said canal, and the settling chamber being connected at the bottom thereof to the next preceding descension chamber.

7. An apparatus for the continuous fermentation of solution comprising a vessel provided with a plurality of chambers constituting ascension chambers through which fermentation "liquid travels in an ascending path and a plurality of chambers alternately disposed between said ascension chambers constituting descension chambers through which fermentation liquid travels in a descending path, means cooperating with each ascension chamber to impart ascending movement to the fermentation solution, said vessel also being provided adjacent the last descending chamber with a settling chamber through which the liquid travels in an ascending path, a

canal located at the bottom of the vessel and leading from the settling chamber to the first ascension chamber, each ascension chamber having an opening at the top thereof to connect the respective ascension chamber to the descension chamber next in advance thereof, each ascension chamber having an opening adacent the bottom thereof to connect the respective ascension chamber to the next preceding descension chamber, the openings adjacent the bottom of said ascension chambers being connected to said canal, and the settling chamber being connected at the bottom thereof to the next preceding descension chamber.

8. An apparatus for the continuous fermentation of solution comprising a vessel provided with a plurality of chambers constituting ascension chambers through which fermentation liquid travels in an ascending path and a. plurality of chambers alternately disposed between said ascension chambers constituting descension chambers through which fermentation liquid travels in a descending path, means "cooperating with each ascension chamber to impart ascending movement to the fermentation solution, said vessel also being provided adjacent the last descending chamber with a settling chamber through which the liquid travels in an ascending path, a canal located at the bottom of the vessel and leading from the settling chamber to the first ascension chamber, each ascension chamber having an opening at the top thereof to connect the respective ascension chamber to the descension chamber next in advance thereof, each ascension chamber having an opening adjacent the bottom thereof to connect the respective ascension chamchamber, means for feedingfresh fermentation liquid to the first ascension chamber, means for drawing off the spent liquid from the upper part of the settling chamber, and means for drawing off liquid rich in micro-organisms.

9. A method of continuously fermenting nutrient solutions comprising circulating said nutrient solution in an alternating ascending and descending path, stirring said solution to maintain the microorganisms in suspension in said nutrient solution until the latter is fermented, conducting the resultant nutrient solution and microorganisms suspended therein in an ascending path, settling at least a portion of the microorganisms in the said last named ascending path, supplying at least a portion of the settled microorganisms and a portion of the consumed nutrient solution with fresh nutrient solution to the initial ascending path, and continuously removing the remaining part of the consumed nutrient solution with a reduced content of microorganisms.

10. A process of continuously cultivating yeast comprising circulating a nutrient solution in an alternate ascending and descending path, aerating said solution to maintain the yeastin suspension in the nutrient solution until the latter is fermented, conducting the nutrient solution and yeast suspended therein in an ascending path,

settling at least a portion of the yeast in the said last ascending path, supplying at least a portion of the settled yeast and a portion of the consumed nutrient solution with fresh nutrient solution to the initial ascending path and continuously removing the remaining part of the consumed nutrient solution with a reduced content of yeast.

11. A process for the continuous fermentation of nutrient solutions comprising circulating a. nutrient solution containing microorganisms suspended therein in an alternate ascending and descending path with continuous progressive consumption of the nutrient, aerating the solution in only the ascending portion of the path succeeded by a descending portion of the path to maintain the microorganisms in suspension therein until the solution is fermented, dividing said solution in the last ascending portion of the path into a sub-division rich inmicroorganisms and into a subdivision poor in microorganisms, conducting by the effect of gravity a portion of the sub-division rich in microorganisms to the beginning of the path of travel of entering fresh nutrient solution in such a manner that some of said portion is admixed with some of the nutrient solution at the lower reversing points of the path and carried through the remainder of said path and drawing off the liquid poor in microorganisms from the upper part of the last ascending portion of the path.

. HEINRICH SCHOLLER.

MAX SEIDEL. 

